/*
* Copyright (c) 2016, Alliance for Open Media. All rights reserved.
*
* This source code is subject to the terms of the BSD 2 Clause License and
* the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
* was not distributed with this source code in the LICENSE file, you can
* obtain it at www.aomedia.org/license/software. If the Alliance for Open
* Media Patent License 1.0 was not distributed with this source code in the
* PATENTS file, you can obtain it at www.aomedia.org/license/patent.
*/
#ifndef AOM_AOM_DSP_PROB_H_
#define AOM_AOM_DSP_PROB_H_
#include <assert.h>
#include <stdio.h>
#include "config/aom_config.h"
#include "aom_dsp/aom_dsp_common.h"
#include "aom_dsp/entcode.h"
#include "aom_ports/bitops.h"
#include "aom_ports/mem.h"
#ifdef __cplusplus
extern "C" {
#endif
typedef uint16_t aom_cdf_prob;
#define CDF_SIZE(x) ((x) + 1)
#define CDF_PROB_BITS 15
#define CDF_PROB_TOP (1 << CDF_PROB_BITS)
/*The value stored in an iCDF is CDF_PROB_TOP minus the actual cumulative
probability (an "inverse" CDF).
This function converts from one representation to the other (and is its own
inverse).*/
#define AOM_ICDF(x) (CDF_PROB_TOP - (x))
#define AOM_CDF2(a0) AOM_ICDF(a0), AOM_ICDF(CDF_PROB_TOP), 0
#define AOM_CDF3(a0, a1) AOM_ICDF(a0), AOM_ICDF(a1), AOM_ICDF(CDF_PROB_TOP), 0
#define AOM_CDF4(a0, a1, a2) \
AOM_ICDF(a0), AOM_ICDF(a1), AOM_ICDF(a2), AOM_ICDF(CDF_PROB_TOP), 0
#define AOM_CDF5(a0, a1, a2, a3) \
AOM_ICDF(a0) \
, AOM_ICDF(a1), AOM_ICDF(a2), AOM_ICDF(a3), AOM_ICDF(CDF_PROB_TOP), 0
#define AOM_CDF6(a0, a1, a2, a3, a4) \
AOM_ICDF(a0) \
, AOM_ICDF(a1), AOM_ICDF(a2), AOM_ICDF(a3), AOM_ICDF(a4), \
AOM_ICDF(CDF_PROB_TOP), 0
#define AOM_CDF7(a0, a1, a2, a3, a4, a5) \
AOM_ICDF(a0) \
, AOM_ICDF(a1), AOM_ICDF(a2), AOM_ICDF(a3), AOM_ICDF(a4), AOM_ICDF(a5), \
AOM_ICDF(CDF_PROB_TOP), 0
#define AOM_CDF8(a0, a1, a2, a3, a4, a5, a6) \
AOM_ICDF(a0) \
, AOM_ICDF(a1), AOM_ICDF(a2), AOM_ICDF(a3), AOM_ICDF(a4), AOM_ICDF(a5), \
AOM_ICDF(a6), AOM_ICDF(CDF_PROB_TOP), 0
#define AOM_CDF9(a0, a1, a2, a3, a4, a5, a6, a7) \
AOM_ICDF(a0) \
, AOM_ICDF(a1), AOM_ICDF(a2), AOM_ICDF(a3), AOM_ICDF(a4), AOM_ICDF(a5), \
AOM_ICDF(a6), AOM_ICDF(a7), AOM_ICDF(CDF_PROB_TOP), 0
#define AOM_CDF10(a0, a1, a2, a3, a4, a5, a6, a7, a8) \
AOM_ICDF(a0) \
, AOM_ICDF(a1), AOM_ICDF(a2), AOM_ICDF(a3), AOM_ICDF(a4), AOM_ICDF(a5), \
AOM_ICDF(a6), AOM_ICDF(a7), AOM_ICDF(a8), AOM_ICDF(CDF_PROB_TOP), 0
#define AOM_CDF11(a0, a1, a2, a3, a4, a5, a6, a7, a8, a9) \
AOM_ICDF(a0) \
, AOM_ICDF(a1), AOM_ICDF(a2), AOM_ICDF(a3), AOM_ICDF(a4), AOM_ICDF(a5), \
AOM_ICDF(a6), AOM_ICDF(a7), AOM_ICDF(a8), AOM_ICDF(a9), \
AOM_ICDF(CDF_PROB_TOP), 0
#define AOM_CDF12(a0, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10) \
AOM_ICDF(a0) \
, AOM_ICDF(a1), AOM_ICDF(a2), AOM_ICDF(a3), AOM_ICDF(a4), AOM_ICDF(a5), \
AOM_ICDF(a6), AOM_ICDF(a7), AOM_ICDF(a8), AOM_ICDF(a9), AOM_ICDF(a10), \
AOM_ICDF(CDF_PROB_TOP), 0
#define AOM_CDF13(a0, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11) \
AOM_ICDF(a0) \
, AOM_ICDF(a1), AOM_ICDF(a2), AOM_ICDF(a3), AOM_ICDF(a4), AOM_ICDF(a5), \
AOM_ICDF(a6), AOM_ICDF(a7), AOM_ICDF(a8), AOM_ICDF(a9), AOM_ICDF(a10), \
AOM_ICDF(a11), AOM_ICDF(CDF_PROB_TOP), 0
#define AOM_CDF14(a0, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12) \
AOM_ICDF(a0) \
, AOM_ICDF(a1), AOM_ICDF(a2), AOM_ICDF(a3), AOM_ICDF(a4), AOM_ICDF(a5), \
AOM_ICDF(a6), AOM_ICDF(a7), AOM_ICDF(a8), AOM_ICDF(a9), AOM_ICDF(a10), \
AOM_ICDF(a11), AOM_ICDF(a12), AOM_ICDF(CDF_PROB_TOP), 0
#define AOM_CDF15(a0, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13) \
AOM_ICDF(a0) \
, AOM_ICDF(a1), AOM_ICDF(a2), AOM_ICDF(a3), AOM_ICDF(a4), AOM_ICDF(a5), \
AOM_ICDF(a6), AOM_ICDF(a7), AOM_ICDF(a8), AOM_ICDF(a9), AOM_ICDF(a10), \
AOM_ICDF(a11), AOM_ICDF(a12), AOM_ICDF(a13), AOM_ICDF(CDF_PROB_TOP), 0
#define AOM_CDF16(a0, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, \
a14) \
AOM_ICDF(a0) \
, AOM_ICDF(a1), AOM_ICDF(a2), AOM_ICDF(a3), AOM_ICDF(a4), AOM_ICDF(a5), \
AOM_ICDF(a6), AOM_ICDF(a7), AOM_ICDF(a8), AOM_ICDF(a9), AOM_ICDF(a10), \
AOM_ICDF(a11), AOM_ICDF(a12), AOM_ICDF(a13), AOM_ICDF(a14), \
AOM_ICDF(CDF_PROB_TOP), 0
static inline uint8_t get_prob(
unsigned int num,
unsigned int den) {
assert(den != 0);
{
const int p = (
int)(((uint64_t)num * 256 + (den >> 1)) / den);
// (p > 255) ? 255 : (p < 1) ? 1 : p;
const int clipped_prob = p | ((255 - p) >> 23) | (p == 0);
return (uint8_t)clipped_prob;
}
}
static inline void update_cdf(aom_cdf_prob *cdf, int8_t val,
int nsymbs) {
assert(nsymbs < 17);
const int count = cdf[nsymbs];
// rate is computed in the spec as:
// 3 + ( cdf[N] > 15 ) + ( cdf[N] > 31 ) + Min(FloorLog2(N), 2)
// In this case cdf[N] is |count|.
// Min(FloorLog2(N), 2) is 1 for nsymbs == {2, 3} and 2 for all
// nsymbs > 3. So the equation becomes:
// 4 + (count > 15) + (count > 31) + (nsymbs > 3).
// Note that the largest value for count is 32 (it is not incremented beyond
// 32). So using that information:
// count >> 4 is 0 for count from 0 to 15.
// count >> 4 is 1 for count from 16 to 31.
// count >> 4 is 2 for count == 31.
// Now, the equation becomes:
// 4 + (count >> 4) + (nsymbs > 3).
const int rate = 4 + (count >> 4) + (nsymbs > 3);
int i = 0;
do {
if (i < val) {
cdf[i] += (CDF_PROB_TOP - cdf[i]) >> rate;
}
else {
cdf[i] -= cdf[i] >> rate;
}
}
while (++i < nsymbs - 1);
cdf[nsymbs] += (count < 32);
}
#ifdef __cplusplus
}
// extern "C"
#endif
#endif // AOM_AOM_DSP_PROB_H_
